Climate hacks

doi:10.1038/nindia.2017.104 Published online 17 August 2017

Hacking the
climate using two geoengineering tools together – injecting sulphate particles
into the atmosphere and thinning out cirrus clouds – could bring down global
average temperatures and rainfall back to pre-industrial levels, a new study
suggests1. These averages, however, won’t work at a local level due
to the spatial variability of the climate system.

“This is the first
geoengineering climate modelling study to show that both the global mean temperature
and precipitation can be simultaneously restored to pre-industrial levels,”
says Govindasamy Bala, one of the co-authors and a professor at the Centre for
Atmospheric and Oceanic Studies, Indian Institute of Science, Bengaluru. The other
collaborators are from Zhejiang University, Hangzhou, China, and Department of
Global Ecology, Carnegie Institution, Stanford, California, USA.

Geoengineering tools seek to reduce incoming sunlight to fix global warming. In the stratospheric aerosol geoengineering method, sulphate particles are pumped into the stratosphere where they form a layer that obstructs sunlight from getting into the troposphere below, where weather happens. In the cirrus cloud thinning method, thin and wispy cirrus clouds that trap greenhouse gases at high altitudes, are seeded with ice nucleating particles to thin them out.

By combining these two radically different radiation management techniques, the researchers simulated a “cocktail” effect to restore both global mean temperatures and precipitation.

Geoenginering
gets a bad rap because of unintended consequences and also because it sidesteps the goal of reducing carbon emissions. Bala says though the foremost focus should be on CO2 emission reductions, it is also important to continue geoengineering research as all options should be on the table for solving
the climate crisis.